Need IE hoursekeeping help

I’ve been running Internet Explorer 5 for some time now on Windows 95. I need help with two things:

First, IE 4 is still in \IEXPLORE but not in the Add/Remove programs list. (IE 5 went to \Program Files\…)
I can remove the IE 4 directory, but what are the un-needed files in WINDOWS and SYSTEM, etc. (unused .DLL’s etc)??? and old registry keys to remove?

Second, my registry is 3 MB now, very full of {3324…} keys (I think they are classes?) How do I clean out old ones (unused recently) and speed up my system. (It has grown slower the larger the registry has gotten) It would take forever to delete all of them with RegEdit.